As networking continues to expand and diversify, encompassing a growing number of wired and wireless devices, the demand for network monitoring tools remains high. While feature-packed commercial products abound, the growing market for monitoring tools has also fueled robust offerings from the open source community.

We reviewed four popular open source products - Nagios Core 3.5, NetXMS 1.2.7, OpenNMS 1.10.9 and Zenoss Core 4.2. All four products are mature, have extensive monitoring capabilities similar to their enterprise-grade counterparts, and are currently updated with good community support.

The products offer event management, performance monitoring, alerting and reporting on network devices such as servers, routers, switches, printers, UPSs, websites, business applications and mobile devices. Monitoring can be as simple as a PING request to a single device to full-fledged management using SNMP (Simple Network Management Protocol) or a native agent.